1. Field of the Invention
This invention relates to the manufacture of optical fibres and optical fibre preforms.
2. Description of the Prior Art
The previously known method for producing such optical fibres is described in U.S. Pat. No. 3,737,293, issued June 5, 1973 and U.S. Pat. No. 28,028, issued June 4, 1974. In this method the coated bore is collapsed as the tube is drawn during the same operation, which is difficult to control.